<!DOCTYPE html>
<html>
<title>view-transitions: Blend modes are set up only in paired transitions</title>
<link rel="help" href="https://drafts.csswg.org/css-view-transitions-1/">
<link rel="author" href="mailto:vmpstr@chromium.org">

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<style>
div {
  width: 100px;
  height: 100px;
  background: blue;
  contain: paint;
}
.tagone { view-transition-name: one }
.tagtwo { view-transition-name: two }
.tagthree { view-transition-name: three }
.tagfour { view-transition-name: four }
.tagfive { view-transition-name: five }

::view-transition-old(four) {
  animation-name: unset;
}
::view-transition-new(five) {
  animation-name: unset;
}
</style>

<div id=first class=tagone></div>
<div id=second></div>
<div class=tagthree></div>
<div class=tagfour></div>
<div class=tagfive></div>

<script>
async_test(t => {
  assert_implements(document.startViewTransition, "Missing document.startViewTransition");
  let transition = document.startViewTransition(() => {
    first.classList.toggle("tagone");
    second.classList.toggle("tagtwo");
    requestAnimationFrame(() => {
      requestAnimationFrame(() => {
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-image-pair(one)").isolation, "auto"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-old(one)").mixBlendMode, "normal"));

        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-image-pair(two)").isolation, "auto"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-new(two)").mixBlendMode, "normal"));

        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-image-pair(three)").isolation, "isolate"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-old(three)").mixBlendMode, "plus-lighter"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-new(three)").mixBlendMode, "plus-lighter"));

        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-image-pair(four)").isolation, "isolate"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-old(four)").mixBlendMode, "normal"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-new(four)").mixBlendMode, "plus-lighter"));

        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-image-pair(five)").isolation, "isolate"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-old(five)").mixBlendMode, "plus-lighter"));
        t.step(() => assert_equals(getComputedStyle(document.documentElement, "::view-transition-new(five)").mixBlendMode, "normal"));
        t.done();
      });
    });
  });
}, "Blend modes are set up on paired transitions");
</script>
